Get NAV - both latest & historic

The investment that an investor makes in a scheme is translated into a certain number of
'Units' in the scheme. Thus, an investor in a scheme is issued units of the scheme.

When the investment activity is profitable, the true worth of a unit goes up; when there are
losses, the true worth of a unit goes down. The true worth of a unit of the scheme is
otherwise called Net Asset Value (NAV) of the scheme.